Wireless devices have been in use for many years for enabling mobile communication of voice and data. Such devices can include mobile phones and wireless enabled personal digital assistants (PDA's) for example. FIG. 1 is a generic block diagram of the core components of such wireless devices. The wireless core 10 includes a base band processor 12 for controlling application specific functions of the wireless device and for providing and receiving voice or data signals to a radio frequency (RF) transceiver chip 14. The RF transceiver chip 14 is responsible for frequency up-conversion of transmission signals, and frequency down-conversion of received signals. RF transceiver chip 14 includes a receiver core 16 connected to an antenna 18 for receiving transmitted signals from a base station or another mobile device, and a transmitter core 20 for transmitting signals through the antenna 18. Those of skill in the art should understand that FIG. 2 is a simplified block diagram, and can include other functional blocks that may be necessary to enable proper operation or functionality.
Generally, the transmitter core 20 is responsible for up-converting electromagnetic signals from base band to higher frequencies for transmission, while receiver core 16 is responsible for down-converting those high frequencies back to their original frequency band when they reach the receiver, processes known as up-conversion and down-conversion (or modulation and demodulation) respectively. The original (or base band) signal, may be, for example, data, voice or video. These base band signals may be produced by transducers such as microphones or video cameras, be computer generated, or transferred from an electronic storage device. In general, the high frequencies provide longer range and higher capacity channels than base band signals, and because high frequency radio frequency (RF) signals can propagate through the air, they are preferably used for wireless transmissions.
There are several different wireless communications standards that voice and data can be provided in. Such standards (referred to as modes) include WCDMA, EDGE and GSM for example, where each has different electrical and protocol specifications which must be followed. Currently, multi-mode and multi-band compatible transceivers, referred to simply as multi-standard transceivers, are desirable to enable every user equipment, such as a cellular phone, to function in different countries or with different service providers who operate with different communication standards.
Therefore, transceiver integrated circuits (IC) integrate various transmitters with either the same or different transmitter architectures for WCDMA/EDGE/GSM applications. Under tremendous pressure to ship products as quickly as possible to the market, these products lack sufficient research and development efforts, and consequently the IC is either not competitive on silicon area and/or power consumption. Some prior art designs have dedicated signal paths or hardware for each of the WCDMA/EDGE/GSM standards, and some may even have separate low-band and high-band signal paths. This results in larger silicon area of the transceiver chip, and higher power consumption. Recently, the system on chip (SOC) digital transceiver has become very popular, where multi-mode and multi-band radio with the baseband circuits are integrated together using low cost deep submicron CMOS fabrication technology, and operated from low supply voltage. In SOC designs, chip area consumption by the circuits is a significant cost factor since the chip is inherently increased in size over a dedicated transceiver chip or base band processor chip.
It is, therefore, desirable to provide a multi-standard transmitter core architecture that minimizes silicon area consumption.